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    <title>Document</title>
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    <script>
      var arr = [1, 2];
      Array.prototype.abc = function () {
        console.log('haha')
        
      };
      arr.abc()

      var str = 'abc'
      String.prototype.age=function(){
        console.log('xixi')
      }
      str.age()
      
    </script>
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